Solar Power Optimizer Control for Panel-Level MPPT and Voltage Regulation
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Solution Overview
Problem
Solar power systems with multiple solar panels face inefficiencies in converting variable DC voltage to AC power, as existing inverter systems struggle to maximize energy output due to limitations in tracking the maximum power point of each solar panel.
Innovation Solution
A control method and system comprising a plurality of power modules connected in series, each with a solar panel, capacitor, and power optimizer, where local controllers enable the power optimizer to switch between buck, boost, and pass-through modes based on maximum power point tracking (MPPT) currents, and a central controller regulates the input voltage of the inverter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a string solar inverter system is used to convert variable DC voltage to AC power, then the system can operate with multiple solar panels, but the system cannot maximize energy output from each panel due to inability to track individual maximum power points
Solution Approach 1:
The system divides the solar power conversion into independent segments by connecting each solar panel through its own power optimizer module. Each optimizer independently tracks the maximum power point of its associated panel, allowing individualized optimization without requiring complex centralized control for each panel.
Solution Approach 2:
Power optimizer modules serve as intermediary devices between solar panels and the string inverter. These optimizers contain maximum power point tracking functionality and act as mediators that convert panel output to standardized DC voltage, simplifying the overall system architecture while enabling individual panel optimization.
2Productivity
If power optimizers are added to each solar panel to enable maximum power point tracking, then energy output is maximized, but device complexity and cost increase
Solution Approach 1:
The power optimizer modules are designed as universal components that can be applied to any solar panel in the array. Each optimizer performs multiple functions including maximum power point tracking, voltage regulation, and isolation, providing multi-functionality that justifies the added component while maintaining system simplicity.
3Productivity
If solar panels are connected in series to increase voltage output, then the system can operate more efficiently with the inverter, but voltage stresses across capacitors increase reducing reliability
Solution Approach 1:
The system segments the voltage generation function across multiple power optimizer modules, each handling a portion of the total voltage. This segmentation distributes the voltage stress across individual capacitor banks in each module rather than requiring a single high-voltage capacitor, improving reliability while maintaining series connection benefits for inverter compatibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the efficiency of the solar power system by optimizing energy conversion, allowing for higher voltage generation and improved reliability by reducing voltage stresses across capacitors, thereby increasing overall power conversion efficiency.
Implementation Method 1
A solar power conversion system may include a plurality of solar panels connected in series or in parallel. The output of the solar panels may generate a variable dc voltage depending on a variety of factors such as time of day, location and sun tracking ability.
Implementation Method 2
The power optimizer may be implemented as a four-switch buck-boost converter. The four-switch buck-boost converter is used to increase the energy output from the solar panel by tracking the maximum power point of the solar panel.
Implementation Method 3
solar inverter systems are employed to convert the variable dc voltage of the solar panels to a 120 volts ac power source
Data Source
AI summary
A system includes a plurality of power modules connected in series between two input terminals of an inverter, a plurality of local controllers coupled to their respective power modules, wherein a first local controller of the plurality of local controllers is coupled to a first power module comprising a first solar panel, a first capacitor and a first power optimizer, and wherein the first local controller is configured to enable the first power optimizer to switch among a buck mode, a boost mode and a pass-through mode based upon a maximum power point tracking (MPPT) current of the first solar panel, and a central controller coupled to the inverter, wherein the central controller is configured to regulate an input voltage of the inverter.